New York AGRICULTURAL EXPERIMENT STATION. 175 
this solution removes the last trace of starch in a few mo- 
ments. Equal volumes of this starch solution added to a 5% 
solution of the enzym-containing alcoholic precipitate from a 
carrot broth culture of B. carotovorus underwent no change 
even after nine days’ standing, other than the slight conversion 
toward amylodextrin noted above. The enzym-containing alco- 
holic precipitates from beef broth cuitures were likewise in- 
active. In this respect, again, the carrot-rot organism differs 
from Potter’s white-rot organism of turnip (1901) and agrees 
with Spieckermann’s cabbage rot organism (1902). 
Griiss and Reinitzer, as explained in detail later in this 
paper, have advocated the idea that the cytolytic action of 
barley malt is simply due to diastase and hold that no 
“cytase” as distinct from diastase occurs in such extract. 
Newcombe’s work (1899:81) shows the incorrectness of their 
conclusions as regards malt extract, and we are convinced from 
our experiments that in this soft-rot’ organism we have an 
enzym different from diastase. 
THE ACTION OF THE ENZYM ON THE HOST PLANT 
TISSUES 
THE COMPOSITION AND ORIGIN OF THE MIDDLE LAMELLA. 
Inasmuch as the action of this enzym is chiefly upon the 
middle lamella of the host cell, it will make the subsequent 
discussion of this matter clearer if we briefly review the facts 
as at present understood relating to the composition and origin 
of this portion of the cell membrane. Fortunately, some ex- 
cellent work along this line has been done within recent 
years.U 
Examination of any mature parenchymatous cell, as of car- 
rot or turnip root, shows the middle lamella as a more or less 
clearly defined refractive line through the middle plane of the 
cell walls. On either side, i. e., lying between this and the cell 
cavity is an inner lamella, or, as Allen calls it, “ primary 
wall.” .Where three or more cells meet in mature tissue inter- 
11 See critical reviews of the subject by Green (1901: 298-300) and Allen. 
(1902). 
